IgAN explained
MECHANISM OF DISEASE
IgA nephropathy (IgAN) is characterized by glomerular deposition of immune complexes containing galactose-deficient IgA1 that lead to kidney damage1–5
There are 4 processes or ‘Hits’ involved in the pathogenesis of IgAN:6,7
Image adapted from Suzuki H, et al. 20116
This formation of pathogenic IgA1-containing immune complexes triggers:1–3
Different stages of pathology in IgA nephropathy7
- IgAN at an early stage, with minimal mesangial expansion and preserved glomerular capillary tufts (that is, a network of capillaries) architecture. Periodic acid-silver methanamine, haematoxylin and eosin counterstain, 360× magnification
- Small segmental sclerosis (25%) with capillary collapse (thin arrow) and capsular adhesion (thick arrow). Periodic acid-silver methanamine, haematoxylin and eosin counterstain, 360× magnification
- Significant segmental sclerosis (50% of the glomerular area) with capillary collapse and consolidation (*), hyalinosis (thin arrow) and capsular adhesion (thick arrow). Periodic acid-silver methanamine, haematoxylin and eosin counterstain, 360× magnification
- Advanced glomerulosclerosis or glomerular obsolescence (>75%), with associated tubular atrophy and interstitial fibrosis. Periodic acid-silver methanamine, haematoxylin and eosin counterstain, 180× magnification
Image adapted from Lai KN, et al. 20167
References & footnotes
Abbreviations
GFR, glomerular filtration rate; IgA, Immunoglobulin A; IgA1, Immunoglobulin A-1; IgAN, IgA nephropathy.
References
- Wyatt R, Julian B. IgA Nephropathy. N Engl J Med. 2013; 368:2402–14.
- Barratt J, Feehally J. IgA Nephropathy. J Am Soc Nephrol. 2005; 16:2088–97.
- Boyd JK, et al. An update on the pathogenesis and treatment of IgA nephropathy. Kidney Int. 2012; 81:833–43.
- Aucella F, et al. Proteinuria in the prognosis of IgA nephropathy. Minerva Urol Nefrol. 2009; 61:235–48.
- Remuzzi G, Bertani T. Pathophysiology of Progressive Nephropathies. N Engl J Med. 1998; 339:1448–56.
- Suzuki H, et al. The Pathophysiology of IgA Nephropathy. J Am Soc Nephrol. 2011; 22:1975–1803.
- Lai KN, et al. IgA nephropathy. Nat Rev Dis Primers. 2016; 2:16001.
HQ-SPT-2500012 | Date of preparation: February 2025